Optical imaging techniques such as optical coherence tomography (OCT) or confocal microscopy are frequently used to image biological tissue. Fluids may be introduced into the biological tissue to facilitate the imaging. For example, during OCT imaging of an air-filled lung, the imaging light beam may be distorted or strongly attenuated each time it transitions between an area of tissue and an area filled with air because of the difference in refractive index between the tissue and the air. To reduce such imaging artifacts, the air may be replaced by fluid in the lung lobe being imaged, reducing such artifacts. This is a technique known as bronchoalveolar lavage. In another example, an optical clearing agent such as glycerol may be introduced into a tissue to increase the image penetration depth of an OCT imaging system. In yet another example, a fluorescent contrast agent may be introduced into tissue to enhance the fluorescence of tissue during wide field fluorescence microscopy or confocal microscopy.
Existing methods of fluid introduction for imaging and/or measurement purposes have significant disadvantages. For example, often an excessive amount of the fluid is required, regions other than a region of interest are exposed to the fluid and direction of the fluid to the region of interest and subsequent removal is difficult. There is a need for advancement.